Oligosaccharides were prepared through mild hydrochloric acid hydrolysis of k-carrageenan from Kappaphycus striatum carrageenan. Three oligosaccharides were purified by strong-anion exchange high-performance chromatography. Their structure was elucidated using mass spectral and NMR data. Negative-ion electrospray ionization (ESI) mass spectra at different fragmentor voltages provided the molecular weight of the compounds and unraveled the fragmentation pattern of the k-carrageenan oligosaccharides. 2D NMR techniques, including 1H-1H COSY, 1H-1H TOCSY and 13C-1H HMQC, were performed to determine the structure of a trisulfated pentasaccharide. 1D NMR and ESIMS were used to determine the structures of a carrageenan-derived pentasaccharide, heptasaccharide, and an undecasaccharide. All the oligosaccharides characterized have a 4-O-sulfo-D-galactopyranose residue at both the reducing and nonreducing ends.

Oligomannuronic acids and oligoguluronic acids were prepared by enzymatic hydrolysis of alginate with alginate lyases. The oligosaccharides generated up to degree of polymerization 16 were characterized by high-performance anion-exchange chromatography (HPAEC) with pulsed amperometric detection (PAD) and electrospray ionization mass spectrometry (ESI-MS). Acetate buffer linear gradients were used as mobile phases for separations of oligosaccharides. ESI-MS and HPAEC-PAD are very effective for the analysis and characterization of anionic oligosaccharides.

The potential targets of marine sulfated polymannuroguluronate (SPMG) involved in inhibition of HIV-1 entry were investigated by surface plasmon resonance and flowcytometry. Results indicated that binding of SPMG either to soluble oligomeric rgp120 or to complexed rgp120-sCD4 mainly resided in V3 loop region. In addition, SPMGwas shown to be less accessible for sCD4 when sCD4 had pre-interacted with rgp120, though SPMG perse multivalently bound to sCD4 with relatively low affinity. While the pre-incubation of SPMG with rgp120 caused a partial blockade of rgp120 binding to sCD4, suggesting that SPMG either shared common binding sites on gp120 with sCD4 or masked the docking sites of gp120 for sCD4. Taken together, V3 domain was demonstrated to be the major site mediating interaction of SPMG with complexed rgp120-sCD4. It seems likely that SPMG binds to both rgp120 and sCD4, but has less accessibility for sCD4 when sCD4 has already bound to rgp120. Nevertheless, addition of SPMG either prior to or after the interaction of rgp120 with sCD4 may suppress rgp120 binding to sCD4. The exact pattern of this trimolecular complex formation at the cell membrane-anchored virus level requires further clarification.

The strategy of complex as ligand allowed us to synthesize three new l-oxalato-bridged heterotrinuclear complexes identified as [Cu2Cr(ox)3(Mephen)2] ClO4 (1), [Cu2Fe(ox)3(Mephen)2] ClO4 (2) and [Cu2Fe(ox)3(Me2bpy)2] ClO4 (3), where ox represents the oxalato dianions; Mephen and Me2bpy stand for 5-methyl-1, 10-phenanthroline and 4, 40-dimethyl-2,20-bipyridine, respectively. The three heterotrinuclear complexes have not yet been isolated in crystalline form suitable for X-ray structure analysis, but based on elemental analyses, molar conductivity and magnetic moment (at room temperature) measurements, IR, ESR and electronic spectra studies, it is proposed that these complexes have an oxalato-bridged structure consisting of two copper (II) ions and a chromium (III) or an iron (III) ion, in which the chromium (III) or iron (III) ion has an octahedral environment, and the two copper (II) ions have a square-planar environment. Variable-temperature magnetic susceptibility (4.2-300K) measurements of the complexes 1 and 2 revealed the occurrence of an intramolecular ferromagnetic interaction between the copper (II) and chromium (III) ions for 1. On the other hand, the spin-coupling between the copper (II) and iron (III) ions through the oxalato-bridge in complex 2 is an antiferromagnetic. The magnetic data have been also used to deduce the indicated heterotrinuclear structure. On the basis of the spin-Hamiltonian, ^H% 2Jð^SCu1 ^SMþ ^SCu2 ^SMÞ (M%Cr3þ or Fe3þ), the magnetic analysis was carried out for the two complexes and the spin-coupling (J) was evaluated as +14.9cm 1 for 1 and) 12.7cm 1 for 2.

Two new complexes [Cu(N,N0,N00-(D-Glc)3-tren)Cl]Cl (1) and [Cu(N,N0,N00-(maltose)-tren)] Cl2ÆH2O (2), have been synthesized and characterized by elementary analysis, and the IR and UV spectra suggest that complex 1 and complex 2 are arranged in trigonal bipyramidal configuration and square-pyramidal configuration, respectively. The crystal structure of complex 1 has been determined by X-ray diraction as: a% 9: 3476ð8Þ, b% 17: 4236ð13Þ, c% 9: 7836ð8Þ A, b% 91: 197ð3Þ, V% 1593: 1ð2Þ A3, Z% 2, and R% 0: 0325, which shows that three secondary amine groups (N-1, N-2, N-3) of the glycosylamine ligand forms the equatorial plane, and the tertiary amine (N-4) and one Cl are located at the apical positions.